Asbestos Injury Claims in California Must Be Based on Showing of Causation

Atlantic Legal recently submitted an amicus brief in the California Court of Appeal on behalf of 16 distinguished scientists, including a Nobel laureate in Physics, a former director of the National Center for Toxicological Research, a former editor-in-chief of the New England Journal of Medicine, and a professor emeritus of Biochemistry and Molecular Biology at the University of California, Berkeley and recipient of the National Medal of Science, urging the court to reverse a judgment of the trial court awarding a multimillion dollar judgment for plaintiffs in a case involving liability of a manufacturer of plasterboard joint compound for the pleural mesothelioma (a fatal cancer of the lining of the lungs) of a woman – the wife of a building contractor – whose exposure was limited to her occasional use of joint compound from a variety of manufacturers and asbestos-containing pipe from another company, for a limited period of time. The case is Mahoney v. Georgia Pacific LLC.

There was no dispute that the wallboard joint compound made by Georgia-Pacific contained only chrysotile asbestos. It is also well-established by numerous epidemiological studies that chrysotile asbestos is significantly less likely to cause mesothelioma than amphibole asbestos – by an order of 20 to 50 times lower morbidity and mortality – and that Mrs. Mahoney’s exposure was very substantially – by many orders of magnitude – below the threshold for a causal connection between pleural mesothelioma and chrysotile asbestos.

The principal argument of the Foundations brief was that plaintiffs’ medical causation expert failed to analyze the probability of causation of Mrs. Mahoney’s mesothelioma using the evidence of plaintiffs’ own expert on exposure as to the quantity of chrysotile asbestos to which she was exposed, that his theory of ‘special exposure’ did not take into account numerous recent epidemiological studies showing that chrysotile asbestos is significantly less likely to cause mesothelioma than amphibole asbestos (to which Mrs. Mahoney was exposed in her work with pipes that were cut during the home renovation projects sheworked on as part of the family business), and that his testimony could not, therefore, establish the reasonable medical probability that her exposure was a substantial factor in bringing about the injury, as required by Rutherford v. Owens-Illinois, Inc., the leading California Supreme Court decision on standards of proof of causation in products liability – as particularly asbestos exposure – cases. We argue that the ‘substantial factor’ language and reasoning of Rutherford requires at least some showing – absent in this case – that the quantum of exposure could contribute in more than a de minimis way to the development of the disease.